===================================================================
RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/tmux/tty.c,v
retrieving revision 1.408
retrieving revision 1.409
diff -u -r1.408 -r1.409
--- src/usr.bin/tmux/tty.c	2021/10/25 09:22:17	1.408
+++ src/usr.bin/tmux/tty.c	2021/10/28 18:57:06	1.409
@@ -1,4 +1,4 @@
-/* $OpenBSD: tty.c,v 1.408 2021/10/25 09:22:17 nicm Exp $ */
+/* $OpenBSD: tty.c,v 1.409 2021/10/28 18:57:06 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -2278,17 +2278,25 @@
 	if (tty->flags & TTY_BLOCK)
 		return;
 
-	if (cx > tty->sx - 1)
-		cx = tty->sx - 1;
-
 	thisx = tty->cx;
 	thisy = tty->cy;
 
+	/*
+	 * If in the automargin space, and want to be there, do not move.
+	 * Otherwise, force the cursor to be in range (and complain).
+	 */
+	if (cx == thisx && cy == thisy && cx == tty->sx)
+		return;
+	if (cx > tty->sx - 1) {
+		log_debug("%s: x too big %u > %u", __func__, cx, tty->sx - 1);
+		cx = tty->sx - 1;
+	}
+
 	/* No change. */
 	if (cx == thisx && cy == thisy)
 		return;
 
-	/* Very end of the line, just use absolute movement. */
+	/* Currently at the very end of the line - use absolute movement. */
 	if (thisx > tty->sx - 1)
 		goto absolute;